A south Wales engineering company is using 21st Century technology, including air bags, to help preserve one of Egypt's most imposing landmarks, dating back to 2,700 BC.

The Pyramid of Djoser is Egypt's oldest step-built pyramid. But it was at risk of collapse after an earthquake in 1992.

Newport specialist engineers Cintec, who have previously provided solutions to structural problems at landmarks such as the White House and Windsor Castle, were set the task of helping it last another 4,700 years.

The team has now completed phase one of the work at the site at Saqqara, south west of Cairo.

It involved using pressurised air-filled bags, in order to hold up the roof of the 60m high pyramid, while more permanent repairs are carried out.

However, Peter James, managing director of Cintec, says this is just the first step in a project which has been complicated by the recent political upheaval in Egypt.

It was a lethal and massive game of Ker-PlunkPeter James, Cintec Engineering

"We were all packed and ready to begin work in January, just when the Egyptian government began to fall," said Mr James.

"We've had to sit on our hands for another four months before getting the go-ahead; all the while hearing stories of looting, and worrying about how much additional damage was going to be caused."

"Fortunately, even though most of our computers and equipment were stolen, the pyramid itself wasn't touched; which is just as well considering how unstable it was when we got in there."

Mr James, who started his career as a buildings inspector for Cardiff Council, said, even with the amount of preparation they'd done, they still weren't prepared for quite how badly damaged the supporting ceiling of the burial chamber really was.

"The earthquake had essentially shifted everything sideways, and an 8m section, in the shape of an inverted cup, had dropped out."

"Until we got the scaffolding in place, we had no idea what was holding up the remaining 60m of stone."

"It was a lethal and massive game of Ker-Plunk; trying to hold everything up, without dislodging anything further."

The air bag technology Cintec employed, was originally created by Mr James to aid in the safer disposal of IEDs in Afghanistan.

It works on the principal of surrounding an explosive with a bag, strong enough to withstand an explosion or collapse, but with such precise control over the pressure, that it only just kisses the surface of an object, without adding even greater forces to unstable materials.

However in the case of the Pyramid of Djoser, Mr James was forced to adapt his technology; substituting a water filling for compressed air.

"We'd originally planned to use our Water Wall system, but as soon as we got a good look at the chamber, it was clear that inflating the bags with water wasn't going to work."

Image caption
The pyramid is at Saqqara, south of Cairo

"The rocks in the ceiling were too jagged, and posed an unacceptable risk of deluging the 4,500-year old pyramid, which has been bone-dry since it was built.

"But also we hadn't realised that there were secret tunnels running under the chamber's floor, so I didn't think it would be able to take the weight of water-filled supports."

Knitted together

"So we used the delays to stress-test our system with a compressed air filling. We needed them to withstand 12 kilonewtons per square metre, but they actually did better than we could possibly imagine, comfortably supporting 28!"

The step pyramid was built above the tomb of pharaoh Djoser, a warrior who reigned in the Old Kingdom in the third dynasty for 19 years. Mummified remains were excavated in the 1930s.

Eleven air pillars now hold up the pyramid's roof, with another six, flatter, bespoke columns currently being manufactured to support the lower corners of the burial chamber.

Once stable, Mr James and his team will perform a permanent repair, threading the latest in thermo-dynamic steel rods diagonally through the steps of the pyramid, in such a way that the six levels will be knitted together without being visible.

The steel, which Cintec have previously used to improve the bomb-resistance of major landmark buildings around the world, is designed to expand and contract with the pyramid, under the extreme temperatures of the desert.

Their final task will be to reclaim as many of the fallen original rocks as possible, and re-point them with authentic 2,700 BC mortar.

"The really tricky parts are the visible bits of the pyramid."

"Underneath the surface we're able to use 21st Century technology to make it as strong as we know how to, but on the outside it needs to be 100% authentic."

"That's involved finding the strongest blend, by testing hundreds of combinations of mortar, all entirely made from components which would have been available to the ancient Egyptians."